1. Field of the Invention
This invention relates to knives, and more particularly to a utility knife for cutting of sheet material such as plasterboard or the like.
2. Background of the Art
Plasterboard (often referred to as drywall or sheetrock) is sold in standard size sheets, typically of 4'.times.8' size. When plasterboard is installed as a wall cladding, it is often necessary to cut a strip of uniform width from a standard sheet, for example to provide a partial sheet for installation in a corner of a room. A professional installer will cut the strip using a utility knife in conjunction with a tape measure. Using his thumb, he will hold the end of the tape measure against the side of the utility knife, extend the tape across the sheet, and hold the tape reel against the edge of the sheet. With the reel held in one hand and the knife in the other, the installer will simultaneously slide both hands down the sheet so that the knife will score a line parallel to the edge. The tape measure is then set aside and a final cut is made along the score line using the knife. The strip to be cut off is then bent with respect to the remainder of the sheet until it snaps along the cut line. Generally, it would not be possible for the installer to apply sufficient pressure to the knife to make the required cut in one pass.
It will be appreciated that this operation is somewhat inconvenient and is time consuming in that two passes with the knife are required. If the installer presses too hard with the knife on the first pass, there is the risk that an inaccurate cut will be made or that the operator may injure himself on the knife blade. There is also the problem that the tape measure may slip.
U.S. Pat. No. 2,952,025 to Johnson, discloses a utility knife having a built-in tape measure for facilitating cutting of plasterboard sheets and the like in the manner discussed above. So far as is known, the Johnson device is not commercially available. However, it is thought that the device would be expensive to manufacture and somewhat cumbersome. Also, there would be the disadvantage that the tape measure could not conveniently be used other than in association with the knife.
U.S. Pat. No. 4,255,856 to Mackie discloses a utility knife attachment in the form of a thin metal plate which is fitted to the handle of the knife alongside the blade and which has a projecting flange at its outer end formed with a slot for receiving a measuring tape.
The following are other examples of patents relating to tape measures associated with scissors for facilitating similar cutting operations on fabrics and the like: U.S. Pat. Nos. 786,646 (J. Johnson); 1,218,798 (Nelson); 2,023,408 (Coll); 2,023,409 (Coll); 2,952,025 (F. H. Johnson).
There is yet a need for a simple but improved means for removably securing the end of a measuring tape to a utility knife.